Efectos de la microalga tóxica Karenia selliformis en los estados larvales de Choromytilus chorus.
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Date
2024
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Universidad de Concepción
Abstract
Karenia selliformis es una microalga tóxica presente en las floraciones algales nocivas (FAN) de la cual se han reportado cada vez más eventos en las costas del sur de Chile. Estas floraciones afectan directamente a la economía del país, ya que en esta zona existen actividades de acuicultura y mitilicultura de gran importancia comercial. En mitílidos, nos encontramos con falta de información del impacto que estas microalgas tóxicas generan en ellos. El objetivo de este estudio fue evaluar el efecto de la exposición directa a las células y exudado de Karenia selliformis en fase exponencial, sobre los estados larvales tempranos de Choromytilus chorus (larvas D, D tardía, umbonada y pre-asentamiento). Este efecto consideró la comparación en la supervivencia, estado del velo, comportamiento natatorio y actividad locomotora de las larvas expuestas a exudado y cultivo completo, respectivamente, a las 24 horas y 48 horas post exposición. Los resultados mostraron que larvas expuestas directamente al cultivo de K. selliformis tuvieron mayores mortalidades respecto a larvas expuestas al exudado. Sin embargo, a pesar de no ser letal, se observaron efectos subletales mayores en larvas expuestas a exudado, como velos sin una cobertura total de la concha y nados acelerados respecto a las que se encontraban en agua de mar. Entre los diferentes estadios larvales, se observó una mayor sensibilidad en larva D expuesta tanto a exudado como a cultivo completo de K. selliformis. Esto nos indica que tanto las células de K. selliformis como su exudado tiene efectos negativos letales y subletales sobre los estadios larvales tempranos de C. chorus, esto se vuelve un problema ya que la producción de la mitilicultura depende de bancos de semillas en el medio natural, donde están expuestas a estas FAN, pudiendo involucrar grandes pérdidas económicas.
Karenia selliformis is a toxic microalgae present in harmful algal blooms (HABs) of which more and more events have been reported in the coasts of southern Chile. These blooms directly affect the country's economy, since in this area there are aquaculture and shellfish farming activities of great commercial importance. In mithilids, there is a lack of information on the impact that these toxic microalgae have on them. The objective of this study was to evaluate the effect of direct exposure to Karenia selliformis cells and exudate in exponential phase on the early larval stages of Choromytilus chorus (D, late D, umbonate and pre-settlement larvae). This effect considered the comparison in survival, veil state, swimming behavior and locomotor activity of larvae exposed to exudate and complete culture, respectively, at 24 hours and 48 hours post-exposure. The results showed that larvae directly exposed to K. selliformis culture had higher mortalities than larvae exposed to exudate. However, despite not being lethal, greater sublethal effects were observed in larvae exposed to exudate, such as veils without total shell coverage and accelerated swimming compared to those in seawater. Among the different larval stages, a higher sensitivity was observed in larva D exposed to both exudate and complete culture of K. selliformis. This indicates that both K. selliformis cells and their exudate have negative lethal and sublethal effects on the early larval stages of C. chorus, which becomes a problem since the production of miticides depends on seed banks in the natural environment, where they are exposed to these FAN, which can involve great economic losses.
Karenia selliformis is a toxic microalgae present in harmful algal blooms (HABs) of which more and more events have been reported in the coasts of southern Chile. These blooms directly affect the country's economy, since in this area there are aquaculture and shellfish farming activities of great commercial importance. In mithilids, there is a lack of information on the impact that these toxic microalgae have on them. The objective of this study was to evaluate the effect of direct exposure to Karenia selliformis cells and exudate in exponential phase on the early larval stages of Choromytilus chorus (D, late D, umbonate and pre-settlement larvae). This effect considered the comparison in survival, veil state, swimming behavior and locomotor activity of larvae exposed to exudate and complete culture, respectively, at 24 hours and 48 hours post-exposure. The results showed that larvae directly exposed to K. selliformis culture had higher mortalities than larvae exposed to exudate. However, despite not being lethal, greater sublethal effects were observed in larvae exposed to exudate, such as veils without total shell coverage and accelerated swimming compared to those in seawater. Among the different larval stages, a higher sensitivity was observed in larva D exposed to both exudate and complete culture of K. selliformis. This indicates that both K. selliformis cells and their exudate have negative lethal and sublethal effects on the early larval stages of C. chorus, which becomes a problem since the production of miticides depends on seed banks in the natural environment, where they are exposed to these FAN, which can involve great economic losses.
Description
Tesis presentada para optar al título profesional de Bióloga Marina
Keywords
Microalgas tóxicas, Choro zapato, Biodiversidad marina